shotguns ain't rifles. There is no rifling to consider (or to get worn either...). So you need to look at them completely differently. Each shotgun is different as to what type and brand of slug it likes. Assuming there is nothing wrong with the gun, and that the stock bolt is tight, and nothing is rattling loose you can generally get pretty good accuracy with slugs. This also really depends on whether you are shooting with a bead, sights, or an optic. Your post is really too vague to answer the way you have framed the question. Maybe a little more detail would help.